— A tractor-trailer already was on fire as it came across a median and crashed into a tour bus Thursday, killing 10 people, according to a couple whose car was sideswiped by the big rig.

Joe and Bonnie Duran said a FedEx truck heading south careened toward them, struck their rental car and crashed into the oncoming bus carrying high school students from Southern California. The bus and truck quickly were engulfed in flames.

Five students from the Los Angeles area, three chaperones and the drivers of both vehicles died in the crash about 100 miles north of Sacramento. Dozens were injured, some critically.

The bus was carrying 44 students to visit Humboldt State University in far northern California. Michael Myvett and his fiancee, Mattison Haywood, both from Los Angeles, were two of four chaperones. Both were killed.

Myvett, who graduated from Humboldt with a psychology degree in 2007 and worked with autistic children, was eager to make the trip with the woman he proposed to on bended knee in Paris last December, said friends and co-workers.

The bus carried a lot of dreams. It was one of three chartered to bring prospective students, many of them hoping to be the first in their families to attend college, to tour Humboldt before they got busy with prom and graduation.

The identical twin 17-year-old daughters of the Serrato family set off on the adventure on separate buses Thursday. Marisol made it to their destination, but the family had no word on Marisa for nearly 24 hours. They received the official word Friday evening when dental records confirmed Marisa was among the dead.

“Marisol is devastated,” said Miguel Serrato, the girls’ 23-year-old brother.

Another victim was Adrian Castro, 19, a senior football player at El Monte High School east of Los Angeles. Castro considered going to a state university closer to his family but decided to give faraway Humboldt — home of sports teams known as the Lumberjacks — a chance, his father, Raul Castro, told the San Gabriel Valley Tribune.

“He told me two days ago, ‘Should I go up and check it out anyway?’ ” said Raul Castro, who dropped his son off to meet the bus Thursday morning. Later that night he got a call from Adrian’s mother, who said she had heard from the California Highway Patrol that the young man had died.

Rescuers said the people who were killed were found mostly at the front of the bus or outside on the ground in front of it. Most survivors were injured, some with critical burns or broken limbs.

Those who made it out said they scrambled through a kicked-out window. Some ran or staggered to the opposite side of Interstate 5 before the bus exploded and was swept by flames.

Humboldt admissions counselor Arthur Arzola, 26, who recruited for the school in the Los Angeles area, was taken to a hospital burn unit in critical condition but died overnight. Arzola was a newlywed studying to be a school counselor at the University of LaVerne in Southern California. He was set to earn his graduate degree in May, LaVerne officials said.

The teenagers aboard, from dozens of different Southern California high schools, were participating in a program that invites prospective low-income or first-generation college students to visit Humboldt.

They were supposed to join hundreds more potential students from across California and the West for a long weekend, pairing up with existing students and staying in the dorms.

Before launching the event Friday, university Vice President Peg Blake’s voice broke as she asked a crowded theater for a moment of silence in honor of everyone affected by the accident.

University President Rollin Richmond says they will welcome back the accident survivors at a time of their choice.

— Associated Press